I've been plagued with what seems an intermittent fail on my mag and I'm stumped for what to check/replace. I had the unit checked and 'Brightsparked' a few seasons ago before Ken's demise. It was ok to start with. This year though it has a mind of its own. Sometimes it will spark up, others not. Yesterday after quite a few kicks it fired up for about ten cycles then stopped. A check at the plug and with just the lead showed no suggestion of a spark. I thought it may be a duff plug so checked a few but no difference. Then for a few kicks all my test plugs produced a spark - but once fitted it wouldn't fire up. A second check revealed no spark again. I have previously fitted a spare Brightspark condenser, to eliminate that from the equation. The pick up brush seems intact but the fitting of the acorn nut for the lead does not seem very positive. I was thinking that may the weak link, and next step is to buy a new setup for there. Any thoughts gents?

Hello Btb.

Did you try to take the contacts barker assembly out and give the points
A good clean, and check the isolation between the 2 parts which makes the contact barker?

It would also be a good idea to replace the HT wire.
The lead might be broken inside, so that it sparks in one position
And does not spark when it bent a bit...

Good luck,
Noam.

Thanks Noam. I've not had the points off to check the insulation but I will take a look later tonight. The points are clean, set correct and the timing is as spot on as I will ever get. Breakdown of the insulation at that point isn't something I had thought of.

The HT cable is brand new, cut off the reel, so no breaks inside. But in fairness I had considered that and have checked it out with a different length.

I got chatting to a repair guy today and he thought breakdown of the insulation on the armature might be the problem.

Thanks again, input appreciated.

Duncan

['I got chatting to a repair guy today and he thought breakdown of the insulation on the armature might be the problem...']

I have always thought this a potential problem with the 'brightspark'...

If fitted to a 'used' mag, you have an upgraded and more accessible condenser but you still have an old, shellac coated armature, old slip ring, bearings etc. etc. with the attendant risk that any of these or any other part could fail..

A reconditioned mag costs a lot more but it all gets done...Ian

email (option): ian@wright52.plus.com

I had a bit of a poor spark and narrowed it down to a poor connection between the carbon brush on the mag pick-up and where it meets the HT lead.

There was little and sometimes no continuity (using the audible bleep on a multimeter) between the brush and the end of the pick up and huge resistance. The end of the pick up had a build up of what looked like scale, but scratching it clean seemed to make no difference.

A new mag pick up, new HT lead and new non-suppressed plug cap seems to have sorted it out.

My mag showed all the signs of a failing condensor. I don't think this is the case with my mag as it seems to be OK now even when the bike has really warmed up.

email (option): sacombsashtrees@hotmail.com

I'm having a similar problem... It seems to be the condensor failing when the engine gets hot :-(
So, purchased a complete replacement that's been serviced/overhauled & will fit when the "summer" season is over (did it ever start?)

email (option): fozzie001@hotmail.com